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Question 1 of 20
5%
High-Level Design
medium
A new feature requires changes to both a REST API and the database schema. You want zero-downtime deployment. What strategy lets old and new code coexist during the rollout?
A
Expand-contract: add new DB column as nullable, deploy code writing to both columns, then remove old column
B
Deploy new backend and DB migration simultaneously during a maintenance window
C
Use feature flags to hide new functionality until migration completes
D
Run two parallel databases and sync data with a migration job
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